need some help! Is a grade 10 bolt repairable?

[absolute_DSM]

Tearing apart the car (97GSX) for a simple "restoration" (ridding the car of most rust), I had too little patience to deal with 1 of the 4 bolts holding the subframe(?) up. It kept spinning without the nut loosening. (It let go in the frame somehow)

In a short story, I hacksawed the bolt off (drivers side front bolt) hoping to be able to replace/repair it.

I realize now it was not the right thing to do and after a few attempts to fix/replace the bolt, Im coming to the board for suggestions.

I have holesawed the frame from the bottom, hoping to be able to drop the bolt out and replace it. Problem is, the bolt isnt held in the way I thought, so simple holesawing the frame didnt help. I welded that back up shortly after.

At a last attempt, I tried actually welding a bolt to the previous bolt, with no luck. That was a joke, I couldnt get the weld to penetrate the OEM bolt so it wouldnt hold any amount of torque. (Plus I dont want to do a half ass job like that anyways)

Heres some pics of what Im talking about -
This is the passenger side front bolt for reference as to what kind of bolt im talking about

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And circled are the positions of the 4 bolts holding up the subframe (use your x ray imagination here)

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Anyone had any luck replacing/fixing these bolts? I know these are are very important part to the car and I dont wanna halfass it. I would love to be able to replace the bolt, but Im not understanding how the bolt is actually put in the frame.

ANY help is appreciated....

 

[absolute_DSM]

Not quite the hot topic eh?

I suppose I could have explained that the main problem is that Im unsure how the frame is contructed so Im not quite sure how to get the old bolt out.

Well I picked up a 10.9 grade 90x1.25 pitch bolt and Im going to attempt to get into the frame and replace the bolt. Ill post when Im done if anyone is interested!

 

[absolute_DSM]

Well after hole sawing the frame in a couple places, I find out its not really a bolt. Well, at least if it is, its welded to a 1x1" piece of steel. That piece of steel is fit into a fancy box welded to the frame. Wow. Its a freakin maze in there.



Back to the drawing board, Im gettin pretty pissed off. Im going to try some higher settings on the Lincoln with a different bolt and hopefully get good enough penetration to weld the bolts together with enough strength to hold the subframe. Tonights a drinkin night for sure!!!!!!!

 

[absolute_DSM]

SUCCESS As much as I was pissed earlier, Im just as happy now. Turns out the type of bolt I was using before was not compatible (ferrous) with the OEM bolt. With the new bolt I picked up today (plain, no coatings) I turned the Lincoln up and gave her hell. An hour later and the subframe is back up.


Just for reference if anyone wants to know in the future:
If the threads are all torn up, the bolt snaps off, its too rusty to get off with any means, basically there is no other way to fix the bolt except by welding - you CAN hacksaw the bolt off.
Pick up a nice grade 10.9 bolt or higher (an m12 at least 90mm long for the subframe bolts) and weld it to the OEM bolt.

Love it, drinking time.

 

[1stGenRocks]

do you have any pictures of it welded back together? That doesnt seem like a very good fix.

 

[absolute_DSM]

do you have any pictures of it welded back together? That doesnt seem like a very good fix.

In fact, I do, sorry it took so long. No offense or disrespect, but do you have a better fix? I wish someone could have seen this and given me some advice, it was (and I hope wont again) giving me a hard time.

And no, that was not the "funnest" thing to weld.
I have the subframe back up, all torqued down, with the front suspension on, sitting on wheels. No probs so far. Of course its not on the road yet, so I cant "test" it out. Ill be taking it easy though when I do, if theres any part of the car I dont want to fail, it would be this.

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And yes, I do know it looks like shit. If you read above, you may see the kind of mood I was in. Its all cleaned up now.

 

[EclipseTrbo420A]

If that doesnt work...You may have to go with some heavy duty nuts bolt and washers.

But the differennce is Drilling that out and then running the bolt with washers and lock nuts and such through it all. Godluck and I hope it holds if it doesnt report back and Ill MS a diagram if you didnt get what I mean.

 

[Spoolin98]

I had a hard time removing my subframe too, the key is patience. Those bolts are a pain in the butt, but eventually you can get them off or on. While dropping the subframe I wondered what would happen if I snapped one of those bolts, now I know. Hope your fix works out for you. BTW, what did you torque the bolts to? I couldn't find a spec.

 

[absolute_DSM]

If that doesnt work...You may have to go with some heavy duty nuts bolt and washers.

But the differennce is Drilling that out and then running the bolt with washers and lock nuts and such through it all. Godluck and I hope it holds if it doesnt report back and Ill MS a diagram if you didnt get what I mean.

Yea Im not following that. There really isnt a way to drill the bolt out. Ill MS paint it up real quick.

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yea, figure that one out. I holesawed from the top into the frame, then holesawed through that thick part of the frame to get to the bolt - HOPING I could just pull the bolt out from the top.. thats a no go.

I tried holesawing the bottom of the frame to drop the bolt out and weld it back up.... thats a no go, its FULL of seams.. its a maze, definately not a place to be (you can see where I welded that back up around the bolt)

Conclusion, weld a grade 10 bolt to the other bolt.

I had a hard time removing my subframe too, the key is patience. Those bolts are a pain in the butt, but eventually you can get them off or on. While dropping the subframe I wondered what would happen if I snapped one of those bolts, now I know. Hope your fix works out for you. BTW, what did you torque the bolts to? I couldn't find a spec.

Spoolin, I learned my lesson from this one and bought me a set of air tools and plenty of PB blaster. I had NO problems at all dropping the rear subframe/suspension/gas tank.

Doing it over again, PB blast and impact. Repeat

Spec? Im German. Gutentite. No really, I just torqued it down a bit to get the suspension and wheels on so I could get the rear in the air.

If you happen to find a spec, post it up. I havent looked yet. If I cant find one, Ill go along with this - http://www.stealth316.com/2-3s-fastener-tips.htm